Method of rifling gun-barrels.



INVENTOIYS ATTORNEYS.

Patented Oct. 30.1900.

c. a c. HAMILTON.

METHOD OF BIFLING GUN BARRELS. (Application filed. In 13 1899) (Io lode!IVITNESSES @7/ J4 fi 7 M UNITED STATES PATENT OFFICE.

CLARENCE J. HAMILTON AND COELLO HAMILTON, OF PLYMOUTH, MICHIGAN.

METHOD OF RIFLING GUN-BARRELS.

SPECIFICATION forming part of Letters Patent No. 660,725, dated October30, 1900.

Application filed March 1 3, 1 8 9 9.

To all whom, it may concern:

Be it known that we, CLARENCE J. HAMIL- TON and (lonLIlo HAMILTON,citizens of the United States, residing at Plymouth, county of \Vayne,State of Michigan, have in vented a certain new and useful Improvementin Methods of Rifling Gun-Barrels; and we declare the following to be afull, clear, and exact description of the invention, such as will enableothers skilled in the art to which it pertains to make and use the same,reference being had to the accompanying drawings, which form a part ofthis specification.

Our invention relates to improvements in firearm construction; and itconsists in a new method of making and rifling barrels for firearms.

Our invention is shown in the accompanying drawings, in which- Figure lis a longitudinal sectional view of a rifle-barrel made by our improvedmethod or process, showing a portion of the mandrel. Fig. 2 is alongitudinal view of the steel mandrel around which the rifle-barrel isformed. Fig. 3 is an end view of the sheet of metal from which therifle-barrel is formed in making the cheaper form. Fig. 4: is a similarview showing the second step in forming this barrel. Fig. 5 is a similarView showing the third step, in which the tube is formed. Fig. 6 is asimilar view showing the fourth step, in which the barrel is pressedonto the mandrel. Fig. 7 is a sectional view of/a long barrel andportions of a press, showing the means for forming the barrels of anydesired length with a press of limited power.

In the drawings we have illustrated the forming of rifle-barrels out ofseamless tubing and similar barrels from a strip of sheet metal byfolding and pressing the metal around the mandrel in the process ofmanufacturing the barrel. The object of the construction in each case isto make a rifle-barrel without using the expensive operation of boringand riding. For ordinary purposes the barrel formed from the strip ofsheet metal, as shown and hereinafter described, is suflicient; but thedifference between forming it from the strip of metal with a seam andfrom seamless tubing only involves the slight difference in expensebetween the use of seam- Serial No. 708,847. (No model) less tubing,either of brass or steel, and the use of the sheet metal formed into atube in the process of manufacturing the barrel.

In the manufacture of these barrels we preferably make the barrel of twoparts and of an inner and outer tube. The inner tube is rifled and theouter tube shrunk over it to give the necessary tensile strength to thebarrel. While this is the preferred form used, the barrel may be formedof a single tube of sufficient thickness to provide the proper strength;but such a construction necessitates greater power than that of thepress we prefer to use. Also by using the barrel made in two parts wecan use difierent metal for the inner tube, and metal more suitable formolding around the mandrel, while the metal for the outer tube may beused that is more especially adapted to give strength than to be formedover the mandrel.

In the drawings, Fig. 1 showsa longitudinal sectional view of a barrel,portions being cut away to show the form of the mandrel as well as themanner of constructing the barrel of the two portions.

In the said drawings, A represents the outer barrel, which consists of atube of any suitable metal and of any desired thickness or tensilestrength.

B represents the inner tube of the rifle-barrel. This tubing in the gunnow manufactured by us we prefer tomake of brass, the tube formed overthe mandrel being what is denominated soft brass. In forming this tubeinto a rifle-barrel we first insert the octagon spiral mandrel O, themaximum diameter of the mandrel being approximately of the diameter ofthe tube. 'The tube carrying the spiral mandrel is then placed under thepress in dies suitably formed and arranged to give the pressure of theparts equally around the tube, details of which will be shown in asubsequent application. Sufficient power is provided in the press toforce the soft brass of which the tube is made onto the mandrel withsuch power as to form it onto the mandrel and I allow the mandrel to bewithdrawn. In operating the press we employ suitable means forWithdrawing the mandrel, giving to it suitable rotating movement tocorrespond with the riflin g.

In Figs. 3, 4, and 5 we have illustrated the formation of the interiorbarrel from a strip of sheet metal by the method used by us in themanufacture of air-gun barrels. The use of this construction is to avoidthe expense of drawn tubing and is employed in the manufacture of cheapbarrels, being originally designed byus for the manufacture of asocalled dollar rifle. tube is by a process employed in which the twoedges of the metal are first turned up .and then by a second action ofthe press forced into the tubular form. After the tubeis thus formed inforcing it. onto the mandrel the edges are brought together with suchpower erations of the press, forming only a limited portion of thebarrel at one stroke. This operation We have illustrated in Fig. 7.

outer or free end of the rod D, so that the first stroke of the presswill form the outer end With each of the barrel over the mandrel. strokeof the press the tube is brought forward nearly the length of the spiralmandrel, being rotated as it is moved to correspond with the riding. Toprovide for making even and uniform riding, the impressions made at eachstroke should overlap. Suitable automatic machinery is employed formoving and rotating the tubing as the press operates. Any other suitableform of mechanism may be employed for performing this operation, and Wedo not limit ourselves to that shown factu're of these barrels, and suchmachinery will be made the subject of subsequent applic'ations. Informing the riding in short barrels it is not necessary in all cases touse the inner and outer tubing; but sufficient pressure can be given tothe barrel to form it over the mandrel.

While we have expressed herein our preference for the soft metal forforining these barrels, we do not limit ourselves thereto, but the samemay be formed of any metal capable of the manipulation in theseprocesses. The barrel may also be formed by drawing it over the mandrelinstead of pressing it thereon, as before described.

We are aware that it is not a new idea to form the metal arounda mandreladapted to give the rifling to the barrel; but the efforts The formingof the heretofore made have been to forcea short spiral mandrel througha block and then insert a longer mandrel and draw outthe block to thedesired length or to wrap the metal around the mandrel in strips,hammering it to the form of the mandrel as the wrapping proceeds. We arealso aware that barrels so formed have afterward been rolled or pressed;but such method does not involve the idea of reducing the diameter of aplain tube by shrinking it directly over a mandrel and by pressureapplied to the outside of the tube.

What we claim is- 1. The herein-described method of rifling barrelsconsisting of compressing a plain tube onto a suitable mandrel of lessdiameter than the inside of the tube, substantially as described.

2. The herein-described method of rifling barrels consisting ofcompressing a plain tube onto a mandrel adapted to give to the interior'of the barrel suitable ritling by applying pressure to the outside ofsaid tube, substantially as described.

3. The herein-described method of riding barrels consisting ofcompressing a plain tube I of soft metal onto a suitable mandrel underThe 1 mandrel as there illustrated is formed on the sufficient pressureto harden the metal and form a tempered inner surface to the barrel,substantially as described.

4:. The herein-described method of riding gun-barrels consisting offirst forming a tube from sheet metal around a suitable mandrel of lessdiameter than the inside of the tube,

and then compressing the tube so formed to the mandrel by pressureapplied to the outside of the tube, substantially as described.

5. The herein-described method of rifling 1 barrels, consisting ofcompressing a portion of a plain tube onto a suitable mandrel, thenmoving the tube so as to bring another portion of the tube over the mandrel'and repeating the operation, substantially as described. herein,as the same is shown merely to illustrate the method employed by us inthe man u- 6. The herein-described method of rifiing barrels,consistingof com pressinga plain-tube onto a suitable mandrel of lessdiameterth'an 1 the inside of theftube and then shrinking an outer tubeortubes'over the first-named tube,

; substantially-as described.

7. Theherein-described method of rifling barrels,consisting ofcompressinga plain tube onto a suitable mandrel of less diameter than ithe inside bf the tube and then'placingthe rifled tube so formed withinan outer tube or tubes, substantially as described.

In testimony whereof we sign this specification in the presence of twowitnesses.

CLARENCE J. HAMILTON. OOELLO HAMILTON.

Witnesses:

S. E. THOMAS, O. H. FISK.

IIO

